As is well known to those of skill in the art, a light-emitting diode (LED) is a solid state semiconductor device that includes one or more p-n junctions. LEDs emit light when current flows through the p-n junctions thereof. The brightness and energy efficiency of the light emitted by an LED may be directly related to the amount of operating or “drive” current flowing through the p-n junction of the LED. Typically, an LED is designed to operate at a drive current level that provides both high brightness and high energy efficiency. LED-based solid state light fixtures include driver circuits that provide the drive current to the LEDs.
Initially, LEDs were primarily used in specialty lighting applications such as providing back-lighting and/or indicator lights in electronic devices. As the light output and energy efficiency of LEDs has improved, LEDs have been used to form solid state light fixtures such as LED-based light bulbs, downlights, streetlights and the like. These LED-based solid state light fixtures are increasingly replacing conventional incandescent and fluorescent light bulbs in numerous applications including general illumination applications such as lighting for homes and offices. These solid state light fixtures generate less heat, are far more energy efficient and have far longer lifetime as compared to incandescent light bulbs. Solid state LED-based light fixtures also exhibit numerous advantages over fluorescent light bulbs, including better energy efficiency, faster turn-on, better dimmability and longer lifetime. LED-based solid state light fixtures may also generate more aesthetically pleasing light than fluorescent light bulbs, and do not contain mercury.